Hydraulic system for digging machines



Jan. 23, 1962 D. F. PRZYBYLSKI 3,018,010

HYDRAULIC SYSTEM FOR DIGGING MACHINES Filed Oct. 25, 1957 6 Sheets-Sheet 1 FIG-l INVENTOR. DANIEL F. PRZYBYLSKI ATTORNEY Jan. 23, 1962 D. F. PRZYBYLSKI HYDRAULIC SYSTEM FOR DIGGING MACHINES 6 Sheets-Sheet 2 Filed Oct. 23, 1957 DANIEL F. PRZYBYLSKI ATTORNEY Jan. 23, 1962 D. F. PRZYBYLSKI HYDRAULIC SYSTEM FOR DIGGING MACHINES 6 Sheets-Sheet 3 Filed Oct. 23, 1957 l I I I I l 5| I I l I I l I I l I I I I I I I I I I I I I l I I l l I I I I I .y

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HYDRAULIC SYSTEM FOR DIGGING MACHINES Filed Oct. 23, 1957 6 Sheets-Sheet 4 FIG-5 INVENTOR. QANIEL. E PRZYBYLSKI ATTORNEY Jan. 23, 1962 D. F. PRZYBYLSKI 3,018,010

HYDRAULIC SYSTEM FOR DIGGING MACHINES Filed Oct. 25, 1957 6 Sheets-Sheet 5 m INVENTOR. m DANIEL E PRZYBYLSKI w/wa ATTORNEY Jan. 23, 1962 D. F. PRZYBYLSKI HYDRAULIC SYSTEM FOR DIGGING MACHINES 6 Sheets-Sheet 6 Filed Oct. 23, 1957 INVENTOR. F. PRZYBYLSKI BY A TORNEY 3,618,610 HYDRAULIC SYSTEM FOR DIGGING MACHENES Daniel F. Przybyisiri, Winona, Minn, assignor to The Warner & Swasey Company, Cleveland, Ohio, a corporation of Ohio Filed Oct. 23, 1957, Ser. No. 691,906 2 Claims. (Cl. 214--138) This invention is concerned with excavating equipment and particularly with portable excavating equipment and is more particularly concerned with a hydraulic actuating system for controlling the operation of such excavating equipment.

Most excavating equipment of any size, even portable excavating equipment is powered with a combination of mechanical power devices and generally utilizes cables and the like in connection with the operation of the booms and the like, and the working implements carried thereby. The provision of cables and pulleys, therefor, and similar elements for actuating parts of the equipment involves weight and expense and decreases the generally utility of the equipment while increasing the service requirements.

Having the foregoing in mind, an objective of the invention is the provision of a control arrangement for excavating equipment in which all of the operations of the equipment are carried out by hydraulic power.

Another object of this invention is the provision of an hydraulic power system for an excavating machine in which a plurality of different movements of the machinery can be carried out simultaneously without the separate movements detracting substantially from the amount of hydraulic power available for carrying out any of the other movements.

A still further object of this invention is the provision of a control arrangement of the hydraulic power system of an excavating machine in which all of the controls are located in a central position for actuation by the operator of the machinery.

Another object of this invention is the provision of a power unit for use with portable excavating equipment in which the entire power unit is contained in the structure of the excavating unit so as to be movable therewith thus requiring no external source of power.

The several objectives above referred to as well as other objectives of this invention will be more readily apparent upon reference to the accompanying drawings and the following specification wherein like parts bear like reference numbers.

In the drawings:

FIGURE 1 is a perspective view of a truck mounted excavating unit having a hydraulic system according to the present invention.

FIGURE 2 is a side elevational view of the structure of FIG. 1 with the excavating equipment in transport position.

FIGURE 3 is a plan view showing the excavating unit in the position which it occupies when it is collapsed for being transported by the truck on which it is mounted.

FIGURE 4 is a plan view looking down on top of the excavating equipment platform with the power unit and the boom and dipper stick and the operators cab removed therefrom.

FIGURE 5 is a plan view similar to FIG. 4, but taken at a lower level showing the arrangement for turning the excavating equipment platform about its bottom support.

FIGURE 6 is a sectional view indicated by line 6-6 on FIG. 2 showing a stabilizer assembly associated with the device and the hydraulic motor arrangement for actuating the pontoons thereof.

FIGURE 7 is a view showing the entire hydraulic circuit illustrated somewhat diagrammatically and the controls pertaining thereto, and,

FIGURE 8 is a fragmentary view showing an arrangement for limiting the rotative travel of the platform of the excavating unit.

Referring to the drawings more in detail, the arrange ment illustrated in FIG. 1 comprises a truck T on which the excavating unit E is mounted, the said excavating unit comprising a tiltable boom and dipper stick assembly B and with there being provided at the rear end of the truck chassis a stabilizer assembly S to support the loads picked up by the excavating equipment so that these loads will not be imposed directly on the truck chassis.

The truck chassis, indicated at 1, has the excavating unit mounted at its rear end and toward the front of the chassis and to one side thereof is the drivers cab 2. On the other side of the chassis in the front is an engine compartment 3. The truck includes the steerable front wheels 4 and the tandam rear wheels 5.

The chassis 1 is made up of spaced channel members 6 fitted together in any conventional manner to form a rigid chassis unit.

The excavating equipment supported on the chassis has a stationary bottom support plate 7 bolted to the chassis as by the bolts and connecting strips 8. Fixed to the center of plate 7 is a cylindrical support structure 9 which forms the means for rotatably supporting the main platform of the excavating unit. The main platform It) of the excavating unit may consist of vertically spaced plates interconnected by vertical flanges or ribs so as to form a stiff but relatively light unit.

Secured to the bottom of rotary platform 10 in any suitable manner are rollers ll. that engage the track formed about the support structure 9. These rollers assist in supporting and guiding the platform and in transmitting thrusts between the platform and the support plate.

In addition to the engagement of the rollers with the track, there is located in the center of the support structure 9 a vertical post 12 that is engaged by a bearing 13 carried by the platform 10. This forms bearing means for holding the platform on a predetermined vertical axis of rotation.

Mounted on platform in are a pair of spaced brackets 14 which pivotally support between their upper ends the hollow boom 15. Boom 15 has pivoted to its outer end a dipper stick 16 and pivotally connected to the lower end of the dipper stick 16 is an earth working implement 17 which may be a conventional shovel bucket or a back hoe bucket.

The boom 15 is preferably made up of plates welded together or channels welded together to form a hollow box-like structure which is relatively light but which is extremely strong.

Pivotally connected to the boom beneath its pivotal connection to brackets 14 are rams 18 that extend into cylinders 19 that are pivotally supported at their opposite closed ends on the bracket means 2% fixed to platform 10. It will be evident that a supply of pressure fluid to cylinders 19 will cause tilting of boom 15 relative to platform 10.

Pivotally connected to the extreme upper end of dipper stick 16 above its pivotal connection with the end of the boom is a ram 21 that extends into a cylinder 22 which is pivoted at its closed end to a bracket 23 carried on top of the boom. A reversible supply of fluid to cylinder 22 will cause tilting of the dipper stick on the boom.

The earth working implement 17 has connected therewith one end of a link 24 that is pivoted at its other end to ram 25 that extends into cylinder 26 that is pivotally supported at its closed end at 27 inside the dipper stick so that the cylinder is in a protected location. A strut 28 is connected between the dipper stick and the point of connection between ram and link 24 so that a substantial moment arm is had for actuating. the implement throughout its normal travel.

Suitable flexible conduit means, as indicated at 29 and 30 are provided for supplying hydraulic fluid to cylinders 22 and 26 as the boom and dipper stick are moved.

The rotation of platform 10 is also accomplished hydraulically and the arrangement for accomplishing this is illustrated in FIGS. 4 and 5. In these views it will be noted that there is a gear 31 mounted on post 12 that is fixed to the bottom support plate of the excavating unit and meshing with gear 31 are racks 32 supported in proper engagement with the gear by adjustable back up rollers 33 which are mounted on the platform to. The racks 32 are connected with rams that extend into cylinders 34 that have their closed end pivotally. supported as at 35 on platform 10 adjacent the edge thereof. It will be apparent that reversible energization of the motors formed by cylinders 34 and the rams pertaining thereto will cause rotary movement of platform It about the vertical pivot axis of the support structure 9. The platform 10 is arranged to rotate through a full 360 from the stopped position in which itis illustrated in FIGS. 4 and 5. The platform is also illustrated in this position in FIG. 3 and it will be noted that with the platform in this stopped position the boom assembly extends forwardly along the longitudinal axis of the .truck and that the dipper stick portion thereof maybe folded therebeneath so that the implement carried thereby can rest on engine compartment 3. At this time the boom itself may rest on a support frame 36 upstanding at the rear of the engine compartment and this frame 36 may engage the sides of the boom whereby the hydraulic system for the excavating unit may be de-energized and the entire assembly will remain in position on the truck chassis for transport by the truck. The'stabilizer assembly is illustrated in FIG. 6.

In FIG. 6, where the aforementioned stabilizer assembly is illustrated, it will be seen to comprise a transverse ly extending hollow structure 37 fixed to the rear edge of plate 7 and having pivoted to the outer ends thereof pontoons 38 and 39 which are connected with the rams 40 and 41, respectively, and which rams extend into the cylinders 42 and 43, respectively, that are pivotally sup ported at their closed end adjacent the center of frame 37. In FIG. 6 the pontoon 38 is shown elevated to transport position and at this time will be positioned substantially within the limits of the platform 10 so as not to impede travel of the vehicle, while the left hand pontoon 39 is shown moved downwardly byits pertaining motor into ground engaging position so that loads picked up by the excavating unit are not imposed on the springs and running gear of the truck but are instead transmitted to the ground.

The hydraulic circuit by means of which the several fluid motors referred to above are controlled in diagrammatically illustrated in FIG. 7.

To the left side of FIG. 7 is a group of control levers that are positioned Within the operators cab 44 mounted on platform llti to the side of the base of the boom so that the operator of the excavating unit can continuously see the movements of the earth working implement that it operates. These controls comprise levers controlling the boom and dipper stick and two pontoons of the stabilizer assembly and the rotation of the platform, and a foot treadle that controls the movements of the implement carried by the dipper stick.

Hydraulic power for the hydraulic system is provided by a hydraulic pump 45 that is arranged for being driven by an internal combustion engine carried by platform 10 and located within a housing 46. Hydraulic pump 45 is preferably a tandem pump so that one section supplies one portion of the hydraulic circuit and another section supplies another portion thereof whereby different movements of the excavating unit can be carried out simultaneously without any substantial reduction in the quantity or the pressure of the fluid available for carrying out other movements.

In FIG. 7 hydraulic pump 45 will be seen to have a first pressure conduit 47 leading therefrom to a pressure manifold 48 mounted on one side of a group of interconnected valves which have at their other sides an exhaust manifold 49 connected with exhaust conduit 5t) leading to reservoir 51 which is also mounted on platform 10 as will be seen in FIG. 1.

The valve arrangement is such that the pressure manifold 48 supplies pressure to the pressure inlets of all the valves while the exhaust manifold 49 conducts exhaust fluid from all thereof. The entire group of valves consists of normally spring-centered, closed center, four-way valves and the group of valves referred to consists of a valve 52 connected with opposite ,ends of therplatform rotating'cylinders 34. Valve 52 is adapted for being controlled by a link 55 that connects, the valve member thereof with operating lever 56 in the operators cab.

A second valve 57 of the group of valves has one service port plugged and the other service port connected by conduit 58 with the outer end of dipper stick cylin-- der 22 and to which end of the cylinder a supplyv of pressure fluid will cause outward movement of the lower end' of the dipper stick on the boom. Valve 57 has its valve member connected with one leg of the double link 59 leading to lever 60 in the operators cab. A relief valve 61 is connected between conduit 58 and exhaust, conduit 50 to relieve extreme pressure built up in the system.

A third valve of the group at 62 is connected by con duits 63 with opposite ends of one of the stabilizer cyl-- inders for raising and lowering the pertaining pontoon. The valve member of this valve is connected by a link 64 with lever 65 in the operators cab.

The final valve 66, of the group of valves referred to, is connected by conduits 67 with the other one of the stabilizer cylinders for controlling the other pontoon thereof and the valve member or" this valve is connected by link 63 with control lever 69 in the operators cab.

The other section of the dual pump 45 is connected by conduit 70 with a pressure manifold 71 corresponding, generally, to pressure manifold 48. Pressure manifold 71 supplies pressure fluid to a second group of valves which are also normally spring centered, closed center, four-way valves. These valves have their exhaust sides connected with an exhaust manifold 72 that is connected with exhaust conduit 50.

One of the valves of the second group adjacent the pressure manifold is indicated at 73 and is connected by conduits 74 with the opposite ends of the cylinder 26 pertaining to the implement carried by the dipper stick. The valve member of this valve is connected by a link 75 with a crank 76 arranged for actuation by foot treadle 77 located in the operators cab.

A second valve 78, of the second group of valves, has one service port connected by a conduit 79 with the ends of the boom cylinders 15 to which pressure fluid is delivered for lifting the boom on the platform. The other service port of this valve is connected by a conduit 80 through a relief valve 81 with the opposite ends of cylinders l5 and this conduit is also connected through a. relief valve 32 with the exhaust conduit 50. Valve 78 has its valve member connected by a link with control lever 86 located within the operators cab.

The last valve of the second group of valves, indicated at 83 has one service port connected by a conduit 84 with the end of cylinder 22 opposite the connection thereto of conduit 58 and the other service port is plugged. Valve 83 has its valve member connected with the second leg of link 59 which is operated by control lever 60.

The hydraulic control circuit described in detail above is effective for controlling all of the operative movements which are likely to occur in such a manner that a full supply of hydraulic pressure fluid is available therefor are controlled from separate banks of valves. For example the operation of the pontoons is carried out by the upper bank of valves. This operation is one not requiring a continuous supply of hydraulic fluid. The upper bank of valves also supplies the fluid for causing the dipper stick to swing outwardly of the boom and likewise controls the rotation of the platform. These functions seldom occur at the same time and when they do, the movements can be carried out at low pressure.

The other bank of valves controls the supply of fluid for tilting the implement on the dipper stick, for raising and lowering the boom, and for swinging the dipper stick inwardly on the boom.

The rotation of the platform is normally limited by a mechanical stop arrangement generally indicated at 90 and which consists of a stationary abutment mounted on bottom support plate 7 and the pawls carried by the platform 10', each adapted for engaging the stop member in one direction of rotation only. In this manner a full 360 degree of rotation of the platform can be had without any rotation thereof beyond the stopped position and, which excess rotation can be undesirable because of possible harmful effects on the turning motors.

The control of the rotation of the platform can also be accomplished by a hydraulic arrangement illustrated in FIG. 8. In this figure the link 55 leading to the valve member of the turning cylinder control valve 52 has associated therewith, by means of the tension springs 91, a lever 92, pivoted at 93 to platform 10 and carrying at its end opposite its spring connection between the platform 10 and the valve member actuating link, a roller 94 engageable between the cams 95 carried on support plate 7. The arrangement is such that when the platform swings toward the position in which it is supposed to stop, one of the cams 95 will engage roller 94 and shift lever 92 in a direction to move the valve member of the control valve for the turning cylinders into its neutral position thereby bringing the platform to a halt. The resilient connection provided by springs 91 between the actuating link 55 and lever 92 and between lever 92 and platform 10 permit movement of the actuating link to set the platform into rotation but in the opposite direction which it is desired to move the platform from its stopped position.

The described arrangement provides for a complete hydraulic operating system for the excavating unit that permits complete control of all of the movements of the equipment at all times, and with precise control of the amount and speed of the movements and with there being an adequate supply of pressure fluid available at all times for operating all of the various components of the excavating unit.

It is thereby noted that the division of the functions of the several components 'between the two banks of valves permits the provision of a relief pressure pertaining to the upper bank, as provided for by relief valve 61 which may be substantially different than the relief pressure provided for the lower bank by the combination of the relief valves 81 and 82. By this arrangement the boom may be held in an elevated position with a substantial load thereon without there being any danger of the boom dropping due to the hydraulic pressure system being relieved to exhaust because of any of the functions being carried out by the other bank of valves.

The provision of an all hydraulic operating system eliminates all chains, cables, pulleys, sheaves, and most of the usual elements subject to failure and requiring attention and service considerably in excess of what is normally required by the much simpler, more compact, and self-lubricating hydraulic system such as is illustrated in this application.

It will be understood that the present invention may be modified to adapt it to various circumstances and it is accordingly desired to comprehend within the purview of this invention such modifications as may be considered to fall within the scope of the appended claims.

I claim:

1. In an excavating unit; a rotatable platform; a boom pivoted on the platform, a dipper stick pivoted on the outer end of the boom, and the lower end of said dipper stick being adapted for pivotally receiving an earth working implement, hydraulic motors for rotating the platform, for tilting the boom on the platform, for tilting the dipper stick on the boom, and for tilting the implement on the dipper stick, a tandem hydraulic pump on the platform and a driving engine therefor, a bank of remotely placed valves pertaining to each section of the pump and each bank of valves controlling predetermined ones of the motors of said excavating unit, and control lever means for actuation by the operator of the unit to control the movements thereof, a first group of said valves controlling rotation of said platform, and movement of said dipper stick in one direction, and the other bank of said valves controlling movements of said implement, the movements of said boom, and the movements of said dipper stick in the opposite direction.

2. In an excavating unit; a platform, a boom pivoted on a horizontal axis to the platform and extending upwardly and outwardly therefrom, a dipper stick pivoted to the outer end of the boom and extending downwardly therefrom, an earth working implement pivoted to the lower end of the dipper stick, a hydraulic motor connected between the platform and the boom for raising and lowering the boom on the platform, a hydraulic motor connected between the dipper stick and the boom for swinging the dipper stick on the boom, and a hydraulic motor connected between the dipper stick and the implement to move the implement on the dipper stick, a pair of hydraulic pumps, valves connecting one of said hydraulic pumps with one end of the dipper stick motor, a relief valve for relieving pressures above the predetermined value in the one end of the dipper stick motor, other valve means connecting the other of the pumps with the hydraulic motor pertaining to the implement and to the hydraulic motor pertaining to the boom and to the other end of the dipper stick motor, and relief valve means pertaining to the second pump for relieving pressures therein different from the pressures relieved by the first mentioned relief valve.

References Cited in the file of this patent UNITED STATES PATENTS 1,542,981 Armstrong June 23, 1925 1,922,285 Ferris Aug. 15, 1933 2,285,862 Jeffrey June 9, 1942 2,363,860 Gentry Nov. 28, 1944 2,383,172 Wagner Aug. 21, 1945 2,513,762 Huston July 4, 1950 2,680,525 Weatherby June 8, 1954 2,711,257 Apel June 21, 1955 2,754,977 Przybylski July 17, 1955 2,768,499 Pilch Oct. 30, 1956 2,809,756 Bannister Oct. 15, 1957 2,811,265 Wagner Oct. 29, 1957 2,812,872 Perkins Nov. 12, 1957 2,840,254 Bevan June 24, 1958 2,846,096 Beyerstedt Aug. 5, 1958 2,927,706 Mork Mar. 8, 1960 FOREIGN PATENTS 886,121 Germany June 25, 1953 1,167,295 France July 7, 1958 OTHER REFERENCES Multi Purpose Gradall, The Warner and Swasey Co., G5405-704 IOM, copy received in Div. 4, May 31, 1955. (Copy in subclass 132, class 214; pages 2, 3, 4, and 5.) (2 sheets photostat.) 

